Prime Minister David Cameron cancelled his visit to Gibraltar on Thursday after the killing of British Labour MP Jo Cox.
Ms Cox, who became MP in 2015 for Batley and Spen, was shot to death in the early afternoon outside her constituency office in Birstall. A man has been arrested. Police have said they are investigating the murder and are not yet able to release any information.
All campaigning for the referendum has now been suspended.
David Cameron had just landed in Gibraltar when he immediately announced that the planned rally for Thursday evening would be cancelled.
Cameron had intended to attend the Stronger In rally. It was to be the first visit by a UK prime minister to Gibraltar since 1968.
The surprise visit was announced late on Wednesday and received a swift reaction from the Spanish government which expressed its displeasure in an official communiqué.
The Spanish PM Mariano Rajoy, on hearing of the shooting, tweeted ““I condemn the attack on the British MP Jo Cox. Violence has no place in democracy. I wish her a swift recovery. MR.”
Crowds had already gathered in Casemates Square where the rally was to be held at 5.30 pm when news came through that it had been cancelled.
